The aim of this study was to describe the game characteristics and energy requirement in elite squash. Seven players (ranked 1-25 in their national federation, including the world number 1) performed a squash-specific incremental test to volitional exhaustion and 3 squash games simulating competition. Pulmonary gas exchanges, heart rate (HR), and blood lactate concentration ([LA]) were recorded by portable analyzers. Energy expenditure (EE(VO(2))) was evaluated by indirect calorimetry. Temporal structure was determined from video recordings. The mean oxygen uptake (VO(2)), HR, EE(VO(2)), and [LA] were 54.4 +/- 4.8 ml x min(-1) x kg(-1) (86 +/- 9% of VO(2)max reached in the incremental squash test), 177 +/- 10 beats x min(-1) (92 +/- 3% of HRmax), 4,933 +/- 620 kJ x h(-1), and 8.3 +/- 3.4 mmol x L(-1), respectively. Time spent >90% of VO(2)max and HRmax was 24 +/- 29% and 69 +/- 18% of the total match duration, respectively. [LA] was correlated (R = 0.87; p = 0.01) with time spent >90% of VO(2)max. The mean rally duration yielded 18.6 +/- 4.6 s, and 34.6% of the rallies were <10 s, and 32.6% were >21 s. The effective playing time was 69.7 +/- 4.7%. World-standard squash is predominantly a high-intensity aerobic activity with great emphasize on the anaerobic energy systems and a high uncertainty in the course of match play. To improve squash results, coaches should plan training according to the characteristics of the sport. By showing the contribution of the different energy pathways and variables easily controllable during training sessions (e.g., HR, rally duration, lactate), the accurate prescription of conditioning session is improved.